Sixtovigo wrote:...but now the problem is software
How do you know that? What are the symptoms, messages on the VGA screen, etc. making you say that?
Let me give you a quick rundown on the d8b boot sequence:
1. Intel CPU resets, jumps into BIOS code (stored in some kind of ROM) and initializes vital I/O hardware
2. if a HDD is found, the partition table and master boot record (MBR) will be checked (some other boot devices, like ROM, floppy and others are also checked, but not quite relevant here)
3. if a valid and active (bootable) partition is found on HDD, then the MBR will be loaded into a specific segment of the memory and execution passed to that code (standard BIOS procedure - here the normal BIOS operation ends)
4. the boot code usually loads a specific file from the file system (in the case of d8b it is the PME.SYS file in the root directory, which is the Mackie OS loader)
5. usually execution is passed to this newly loaded code, which loads more user code and does with the machine whatever it wants...
Software is involved from the very first point, so which software are you referring to? BIOS? MBR code? SYS loader? Mackie's specific code?
Your 43 problem (which indicates a serial communications issue, as pointed out earlier) might be due to any of the following: BIOS failure (settings and/or firmware), incorrect boot device (floppy in the drive? - or bad BIOS setting), not bootable HDD (invalid/inactive partition, etc.), corrupt MBR code, corrupt PME.SYS file, corrupt mackieos.exe file, failed serial port (bad BIOS setting?) and more, or any combination of these. So, without knowing messages on the VGA display first, it would be very hard to guess even remotely right. All that is fixable by software (including boot files - but not BIOS) will be fixed if you reinstall the OS as described on Mackie's pages.
Hope this helps.